U.S. patent application number 14/502955 was filed with the patent office on 2016-03-31 for assisted discovery scans for indoor position determination.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Subash MARRI SRIDHAR, Sai Pradeep VENKATRAMAN, Gengsheng ZHANG.
Application Number | 20160095051 14/502955 |
Document ID | / |
Family ID | 55585975 |
Filed Date | 2016-03-31 |
United States Patent
Application |
20160095051 |
Kind Code |
A1 |
MARRI SRIDHAR; Subash ; et
al. |
March 31, 2016 |
ASSISTED DISCOVERY SCANS FOR INDOOR POSITION DETERMINATION
Abstract
Techniques for determining a position of a mobile device are
provided. An example of these techniques is a method that includes
performing a passive scan for wireless transceivers proximate to
the mobile device to generate passive scan results, generating a
first wireless transceiver list, comprising a first set of wireless
transceivers, transmitting a request to at least one wireless
transceiver from the first wireless transceiver list requesting
that the at least one wireless transceiver perform a scan,
generating a second wireless transceiver list comprising
identifying information for a second set of wireless transceivers,
proximate to the at least one wireless transceiver, measuring
signals received from wireless transceivers selected from at least
one of the first wireless transceiver list and the second wireless
transceiver list, and determining the position of the mobile device
based at least in part on the signals measured.
Inventors: |
MARRI SRIDHAR; Subash; (San
Jose, CA) ; VENKATRAMAN; Sai Pradeep; (Santa Clara,
CA) ; ZHANG; Gengsheng; (Cupertino, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
55585975 |
Appl. No.: |
14/502955 |
Filed: |
September 30, 2014 |
Current U.S.
Class: |
370/252 |
Current CPC
Class: |
G01S 5/02 20130101; G01S
5/0027 20130101; G01S 5/0289 20130101; H04W 48/16 20130101; H04W
64/006 20130101; G01S 5/0284 20130101; H04W 64/003 20130101 |
International
Class: |
H04W 48/16 20060101
H04W048/16; H04W 48/14 20060101 H04W048/14; H04W 64/00 20060101
H04W064/00 |
Claims
1. A method, on a mobile device, for determining a position,
comprising: performing a passive scan for wireless transceivers
proximate to the mobile device to generate passive scan results;
generating a first wireless transceiver list, comprising a first
set of wireless transceivers; transmitting a request to at least
one wireless transceiver from the first wireless transceiver list
requesting that the at least one wireless transceiver perform a
scan for wireless transceivers; receiving scan results from the at
least one wireless transceiver from the first wireless transceiver
list; generating a second wireless transceiver list comprising
identifying information for a second set of wireless transceivers,
proximate to the at least one wireless transceiver; measuring
signals received from wireless transceivers selected from the first
wireless transceiver list, or the second wireless transceiver list,
or combination thereof; and determining the position of the mobile
device based at least in part on the signals measured.
2. The method of claim 1 wherein the request comprises a wireless
local area network (WLAN) Radio Measurement frame comprising a
Beacon Request.
3. The method of claim 1 wherein the request comprises a request to
perform an active scan for the wireless transceivers.
4. The method of claim 1 wherein the request comprises a request to
perform a passive scan for the wireless transceivers.
5. The method of claim 1 further comprising: periodically
performing additional passive scans for the wireless transceivers
proximate to the mobile device; and updating the first wireless
transceiver list based on results of the additional passive
scans.
6. The method of claim 5, wherein updating the first wireless
transceiver list comprises: removing one or more wireless
transceivers from the first wireless transceiver list responsive to
a signal strength associated with each of the one or more wireless
transceivers from the first wireless transceiver list falling below
a first predetermined threshold.
7. The method of claim 6, wherein updating the first wireless
transceiver list comprises: adding one or more wireless
transceivers that are currently not on the first wireless
transceiver list to the first wireless transceiver list responsive
to the signal strength associated with each of the one or more
wireless transceivers that are currently not on the first wireless
transceiver list exceeding a second predetermined threshold.
8. The method of claim 1, wherein the wireless transceivers
comprise WLAN access points.
9. A mobile device configured for determining a position of the
mobile device, the mobile device comprising: a tangible,
non-transitory computer-readable memory; a transceiver configured
to perform a passive scan for wireless transceivers proximate to
the mobile device to generate passive scan results; a processor
connected to the tangible, non-transitory computer-readable memory
and configured to generate a first wireless transceiver list,
comprising a first set of wireless transceivers; the transceiver
further configured to transmit a request to at least one wireless
transceiver from the first wireless transceiver list requesting
that the at least one wireless transceiver perform a scan for
wireless transceivers and to receive scan results from the at least
one wireless transceiver from the first wireless transceiver list;
the processor further configured to: generate a second wireless
transceiver list comprising identifying information for a second
set of wireless transceivers, proximate to the at least one
wireless transceiver; measure signals received from wireless
transceivers selected from the first wireless transceiver list, or
the second wireless transceiver list, or combination thereof; and
determine the position of the mobile device based at least in part
on the signals measured.
10. The mobile device of claim 9 wherein the request comprises a
wireless local area network (WLAN) Radio Measurement frame
comprising a Beacon Request.
11. The mobile device of claim 9 wherein the request comprises a
request to perform an active scan for the wireless
transceivers.
12. The mobile device of claim 9 wherein the request comprises a
request to perform a passive scan for the wireless
transceivers.
13. The mobile device of claim 9 wherein the processor is further
configured to: periodically perform additional passive scans for
the wireless transceivers proximate to the mobile device; and
update the first wireless transceiver list based on results of the
additional passive scans.
14. The mobile device of claim 13, wherein the processor is further
configured to: remove one or more first wireless transceivers from
the first wireless transceiver list responsive to a signal strength
associated with each of one or more wireless transceivers from the
first wireless transceiver list falling below a first predetermined
threshold.
15. The mobile device of claim 14, wherein the processor is further
configured to: add one or more second wireless transceivers
currently not on the first wireless transceiver list to the first
wireless transceiver list responsive to the signal strength
associated with each of the one or more second wireless
transceivers currently not on the first wireless transceiver list
exceeding a second predetermined threshold.
16. A method for disambiguation of a location context associated
with a mobile device comprising: performing a scan for wireless
transceivers proximate to the mobile device to generate discovery
scan results from the scan for wireless transceivers proximate to
the mobile device; generating a first wireless transceiver list
based on the discovery scan results from the scan for wireless
transceivers proximate to the mobile device, the first wireless
transceiver list comprising a first subset of the wireless
transceivers proximate to the mobile device, and wherein wireless
transceivers in the first subset of the wireless transceivers
proximate to the mobile device are associated with a first location
context identifier (LCI) with which the mobile device is
associated; generating a second wireless transceiver list based on
the discovery scan results from the scan for wireless transceivers
proximate to the mobile device, the second wireless transceiver
list comprising a second subset of the wireless transceivers
proximate to the mobile device, and wherein wireless transceivers
in the second subset of the wireless transceivers proximate to the
mobile device are associated with a second LCI, wherein the second
LCI is different from the first LCI; transmitting a first scan
request to at least one wireless transceiver from the first
wireless transceiver list requesting the at least one wireless
transceiver from the first wireless transceiver list perform a scan
for wireless transmitters proximate to the at least one wireless
transceiver from the first wireless transceiver list; transmitting
a second scan request to at least one wireless transceiver from the
second wireless transceiver list requesting the at least one
wireless transceiver from the second wireless transceiver list
perform a discovery scan for wireless transmitters proximate to the
at least one wireless transceiver from the second wireless
transceiver list; receiving discovery scan results from the at
least one wireless transceiver from the first wireless transceiver
list; receiving discovery scan results from the at least one
wireless transceiver from the second wireless transceiver list;
comparing the discovery scan results from the scan for wireless
transceivers proximate to the mobile device with the discovery scan
results from the at least one wireless transceiver from the first
wireless transceiver list and the discovery scan results from the
at least one wireless transceiver from the second wireless
transceiver list; and determining an LCI associated with a portion
of an indoor environment in which the mobile device is located
based at least in part on results of comparison.
17. The method of claim 16 wherein the first scan request or the
second scan request or both comprise a request to perform an active
scan for the wireless transceivers.
18. The method of claim 16 wherein the first scan request or the
second scan request or both comprise a request to perform a passive
scan for the wireless transceivers.
19. The method of claim 16 wherein determining the LCI associated
with the portion of the indoor environment in which the mobile
device is located based at least in part on results of comparison
further comprises selecting the LCI based on a number of wireless
transceivers included in the discovery scan results from the scan
for wireless transceivers proximate to the mobile device, the
discovery scan results from the at least one wireless transceiver
from the first wireless transceiver list, and the discovery scan
results from the at least one wireless transceiver from the second
wireless transceiver list associated with the LCI.
Description
BACKGROUND
[0001] Many mobile devices utilize position determination
techniques to provide location based-services to the user of the
mobile device, such as navigation applications, map information,
content targeted to the location of the mobile device, and/or other
location-based services. The mobile device can be configured to use
signals from various types of wireless transceivers, including
wireless access points providing Wireless Local Area Network (WLAN)
connectivity and/or wireless base stations providing Wireless Wide
Area Network (WWAN) connectivity (macrocells, picocells,
microcells, femtocells, and/or other types of WWAN base station)
can be used to determine the position of a mobile device.
[0002] The mobile device can be configured to perform scans to
detect wireless transceivers proximate to the mobile device. The
signals from these scans can be used to determine a position of the
mobile device. Performing such scans can require significant
resources on the mobile device, and can significantly impact the
battery life of the mobile device.
SUMMARY
[0003] An example method for determining a position of the mobile
device according to the disclosure includes performing a passive
scan for wireless transceivers proximate to the mobile device to
generate passive scan results, generating a first wireless
transceiver list, comprising a first set of wireless transceivers,
transmitting a request to at least one wireless transceiver from
the first wireless transceiver list requesting that the at least
one wireless transceiver perform a scan for wireless transceivers,
receiving scan results from the at least one wireless transceiver
from the first wireless transceiver list, generating a second
wireless transceiver list comprising identifying information for a
second set of wireless transceivers, proximate to the at least one
wireless transceiver, measuring signals received from wireless
transceivers selected from the first wireless transceiver list, or
the second wireless transceiver list, or combination thereof, and
determining the position of the mobile device based at least in
part on the signals measured.
[0004] Implementations of such a method may include one or more of
the following features. The request comprises a wireless local area
network (WLAN) Radio Measurement frame comprising a Beacon Request.
The request comprises a request to perform an active scan for the
wireless transceivers. The request comprises a request to perform a
passive scan for the wireless transceivers. Periodically performing
additional passive scans for the wireless transceivers proximate to
the mobile device, and updating the first wireless transceiver list
based on results of the additional passive scans. Updating the
first wireless transceiver list includes removing one or more
wireless transceivers from the first wireless transceiver list
responsive to a signal strength associated with each of the one or
more wireless transceivers from the first wireless transceiver list
falling below a first predetermined threshold. Updating the first
wireless transceiver list includes adding one or more wireless
transceivers that are currently not on the first wireless
transceiver list to the first wireless transceiver list responsive
to the signal strength associated with each of the one or more
wireless transceivers that are currently not on the first wireless
transceiver list exceeding a second predetermined threshold. The
wireless transceivers comprise WLAN access points.
[0005] An example mobile device for determining the position of the
mobile device according to the disclosure includes a tangible,
non-transitory computer-readable memory, a processor connected to
the tangible, non-transitory computer-readable memory, and a
transceiver configured to perform a passive scan for wireless
transceivers proximate to the mobile device to generate passive
scan results. The processor is configured to generate a first
wireless transceiver list, comprising a first set of wireless
transceivers. The transceiver is further configured to transmit a
request to at least one wireless transceiver from the first
wireless transceiver list requesting that the at least one wireless
transceiver perform a scan for wireless transceivers and to receive
scan results from the at least one wireless transceiver from the
first wireless transceiver list. The processor is further
configured to generate a second wireless transceiver list
comprising identifying information for a second set of wireless
transceivers, proximate to the at least one wireless transceiver,
measure signals received from wireless transceivers selected from
the first wireless transceiver list, or the second wireless
transceiver list, or combination thereof, and determine the
position of the mobile device based at least in part on the signals
measured.
[0006] Implementations of such a mobile device may include one or
more of the following features. The request comprises a wireless
local area network (WLAN) Radio Measurement frame comprising a
Beacon Request. The request comprises a request to perform an
active scan for the wireless transceivers. The request comprises a
request to perform a passive scan for the wireless transceivers.
The processor is further configured to periodically perform
additional passive scans for the wireless transceivers proximate to
the mobile device, and update the first wireless transceiver list
based on results of the additional passive scans. The processor is
further configured to remove one or more first wireless
transceivers from the first wireless transceiver list responsive to
a signal strength associated with each of one or more wireless
transceivers from the first wireless transceiver list falling below
a first predetermined threshold. The processor is further
configured to add one or more second wireless transceivers
currently not on the first wireless transceiver list to the first
wireless transceiver list responsive to the signal strength
associated with each of the one or more second wireless
transceivers currently not on the first wireless transceiver list
exceeding a second predetermined threshold.
[0007] An example method for disambiguation of a location context
associated with a mobile device according to the disclosure
includes performing a scan for wireless transceivers proximate to
the mobile device to generate discovery scan results from the scan
for wireless transceivers proximate to the mobile device,
generating a first wireless transceiver list based on the discovery
scan results from the scan for wireless transceivers proximate to
the mobile device, the first wireless transceiver list comprising a
first subset of the wireless transceivers proximate to the mobile
device, and wherein wireless transceivers in the first subset of
the wireless transceivers proximate to the mobile device are
associated with a first location context identifier (LCI) with
which the mobile device is associated, generating a second wireless
transceiver list based on the first discovery scan results, the
second wireless transceiver list comprising a second subset of the
wireless transceivers proximate to the mobile device, and wherein
wireless transceivers in the second subset of the wireless
transceivers proximate to the mobile device are associated with a
second LCI, wherein the second LCI is different from the first LCI,
transmitting a first scan request to at least one wireless
transceiver from the first wireless transceiver list requesting the
at least one wireless transceiver from the first wireless
transceiver list perform a scan for wireless transmitters proximate
to the at least one wireless transceiver from the first wireless
transceiver list, transmitting a second scan request to at least
one wireless transceiver from the second wireless transceiver list
requesting the at least one wireless transceiver from the second
wireless transceiver list perform a discovery scan for wireless
transmitters proximate to the at least one wireless transceiver
from the second wireless transceiver list, receiving discovery scan
results from the at least one wireless transceiver from the first
wireless transceiver list, receiving discovery scan results from
the at least one wireless transceiver from the second wireless
transceiver list, comparing the discovery scan results from the
scan for wireless transceivers proximate to the mobile device with
the discovery scan results from the at least one wireless
transceiver from the first wireless transceiver list and the
discovery scan results from the at least one wireless transceiver
from the second wireless transceiver list, and determining an LCI
associated with a portion of an indoor environment in which the
mobile device is located based at least in part on results of
comparison.
[0008] Implementations of such a method may include one or more of
the following features. The first scan request or the second scan
request or both comprise a request to perform an active scan for
the wireless transceivers. The first scan request or the second
scan request or both comprise a request to perform a passive scan
for the wireless transceivers. Determining an LCI associated with a
portion of an indoor environment in which the mobile device is
located based at least in part on results of comparison further
comprises selecting the LCI based on a number of wireless
transceivers included in the discovery scan results from the scan
for wireless transceivers proximate to the mobile device, the
discovery scan results from the at least one wireless transceiver
from the first wireless transceiver list, and the discovery scan
results from the at least one wireless transceiver from the second
wireless transceiver list associated with the LCI.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram of an example network
architecture, which may be suitable for an implementing the
techniques discussed herein.
[0010] FIG. 2 is a block diagram of a mobile device that can be
used to implement the mobile device illustrated in FIG. 1.
[0011] FIG. 3 is a functional block diagram of the mobile device
illustrated in FIG. 2 that illustrates functional modules of the
memory shown in FIG. 2.
[0012] FIG. 4 is a block diagram of a wireless transceiver that can
be used to implement the wireless transceivers illustrated in FIG.
1.
[0013] FIG. 5 is a functional block diagram of the wireless
transceiver illustrated in FIG. 4 that illustrates functional
modules of the memory shown in FIG. 4.
[0014] FIG. 6 is a flow diagram of a process for determining the
position of a mobile device using the assisted discovery scanning
techniques discussed herein.
[0015] FIG. 7 is a flow diagram of a process for providing
assistance data to a mobile device according to the assisted
discovery scanning techniques discussed herein.
[0016] FIG. 8 is a flow diagram of a process for LCI disambiguation
using the passive scanning techniques discussed herein
[0017] FIGS. 9A and 9B are diagrams that illustrate how a wireless
transceivers list may be updated as a mobile device moves through
an indoor environment.
DETAILED DESCRIPTION
[0018] Techniques disclosed herein are configured to provide for
assisted discovery scans in which the mobile device receives
assistance from one or more wireless transceivers proximate to the
mobile device in scanning for wireless transceivers proximate to
the mobile device. The techniques disclosed herein can be applied
to indoor positioning techniques in which the mobile device scans
for one or more wireless transceivers the signals from which can be
used to determine the position of the mobile device. The mobile
device can be configured to perform active and/or passive scans for
wireless transceivers. Example implementations are provided herein
in which the mobile device is configured to request assisted
discovery scans from WLAN wireless access points, but the
techniques disclosed herein are not limited to WLAN wireless access
points and can also be used with other types of wireless
transceivers the signals from which can be used to determine the
position of a mobile device. The wireless transceivers can comprise
wireless transceivers that are located at fixed locations, or the
wireless transceivers may be movable but generally do not change
location, such that the locations of the wireless transceivers can
be used to determine a location of the mobile device.
[0019] The techniques disclosed herein can provide several
advantages over conventional indoor discovery scans performed by
the mobile device. For example, a mobile device using a
conventional discovery scan technique may be configured to perform
either a passive or active scan for nearby wireless transceivers
every ten seconds. The mobile device may take at least three
seconds to scan all of the channels in just the 2.4 GHz band when
performing such a scan. Furthermore, the environment around the
mobile device may be continually changing as the mobile device
moves through the indoor environment, which can negatively impact
the performance of the scan. The technique disclosed herein can
provide improved results over conventional scans where the entire
scan is performed by the mobile device. For example, the detection
range of the mobile device may be much less than that of a wireless
transceiver, such as a WLAN wireless access point or other wireless
transceiver. In the techniques disclosed herein, the wireless
access points are used to perform at least some scanning on behalf
of the mobile device, which may result in scan detecting wireless
transceivers that may have otherwise been missed by the mobile
device due to the increased sensitivity of the wireless
transceivers. The wireless transceivers may also discover wireless
transceivers that do not broadcast identity information (e.g., a
wireless access point that does not transmit it's SSID), because
the wireless transceivers are able to scan multiple channels in
parallel on behalf of the mobile device and can listen longer on
each channel for transmissions that can be used to identify
wireless transceivers that do not broadcast identity information.
Furthermore, by handing off at least a portion of the scan to one
or more wireless transceivers proximate to the mobile device, the
mobile device can conserve power and processing resources that
would otherwise be expended on the discovery scan. The wireless
transceivers typically are powered by an external power supply and
rather than a battery or other such power supply, and thus, are not
constrained by available power available of the battery or other
such power supply.
Example Network Environment
[0020] FIG. 1 is a block diagram of an example network
architecture, which may be suitable for an implementing the
techniques discussed herein. The particular configuration
illustrated herein is merely an example of one network
configuration in which the techniques disclosed herein may be used.
Furthermore, an implementation of such a network architecture may
include additional elements that are not illustrated herein and
have been omitted for the sake of clarity.
[0021] The mobile device 120 may also be referred to as a User
Equipment (UE), a mobile station, a terminal, an access terminal, a
subscriber unit, a station, etc. The mobile device 120 may be a
smartphone, a tablet computer, a laptop computer, or other device
that includes a wireless transceiver that is configured to
communicate using one or more wireless communications protocols,
including, but not limited to, the Long Term Evolution (LTE), WiFi,
and WiMAX wireless communications protocols. The mobile device 120
can also be configured to support other types of wireless
communications protocols and can be configured to support multiple
different wireless communications protocols. The wireless
transceiver of the mobile device 120 can be configured to send data
to and/or receive data from other mobile devices 120, the wireless
transceivers 115, and/or one or more wireless base stations
140.
[0022] The mobile device 120 can be configured to include a Global
Navigation Satellite System (GNSS) receiver configured to receive
and measure signals from one or more satellites 170, such as
satellites 170a and 170b, and to obtain pseudo-range measurements
for the satellites 170. Satellites 170 may be part of a Global
Navigation Satellite System (GNSS), which may be the United States
Global Positioning System (GPS), the European Galileo system, the
Russian GLONASS system, or some other GNSS. The GNSS receiver may
also be configured to detect and receive signals from satellites
170 belonging to more than one GNSS system. For example, satellite
170a could belong to the GPS system while the satellite 170b could
belong to the Galileo system. While the example network
architecture illustrated herein illustrates only two satellites
170, other implementations may have more or less satellites
available, may have satellites associated with one or more GNSS
system, and the number of satellites visible to the mobile device
120 may depend upon the current geographical location of the mobile
devices and the orbits of the satellites 170.
[0023] The mobile device 120 may also measure signals from one or
more wireless base stations or wireless access points, such as the
terrestrial wireless transceivers 115 and the macrocell base
station 140, and obtain timing measurements (e.g., for time of
arrival (TOA) or observed time difference of arrival (OTDOA)),
signal strength measurements (e.g., Receive Signal Strength
Indication (RSSI)), and/or signal quality measurements for the
wireless base stations. The pseudo-range measurements, timing
measurements, signal strength measurements, and/or signal quality
measurements may be used to derive a location estimate for the
mobile device 120. A location estimate may also be referred to as a
position estimate, a position fix, etc. Two terrestrial wireless
transceivers are illustrated in this example: 115a and 115b.
However, in other implementations, more or less wireless
transceivers 115 may be included. For example, the network
environments illustrated in FIGS. 9A and 9B include more wireless
transceivers 115 to illustrate specific aspects of the techniques
disclosed herein. The mobile device 120 can also be configured to
use a combination of signals from one or more of the satellites
170, the macrocell base station 140, and/or the wireless
transceivers 115 to determine a position of the mobile device
120.
[0024] Each of the wireless transceivers 115 can comprise a WLAN
wireless access point configured to operate using the IEEE 802.11
wireless communication standards. But, in some implementations some
or all of the wireless transceivers 115 may be configured to
utilize other wireless communications protocols, and some network
environments may include a more than one type of wireless
transceiver 115. The terrestrial wireless transceiver 115 can be
connected to network 110 via a backhaul connection that provides a
broadband connection to the network 110. The network 110 may be the
Internet and/or a combination of one or more networks. For example,
the terrestrial wireless transceiver 115 may be connected to a DSL
modem or a cable modem, depending upon the type of broadband
service being used in that particular implementation. A wireless
transceiver 115 can be associated with a mobile communication
network provider and can be configured to communicate with the
mobile communication network provider's network (not shown) via the
network 110. The coverage area of the a wireless transceiver 115
may overlap with that of one or more macrocell base stations, such
as macrocell base station 140, or that of one or more other
terrestrial transceivers.
[0025] The wireless base station 140 can be configured to provide
wireless network connectivity to a plurality of mobile devices 120.
The wireless base station 140 may comprise a macrocell base station
or other type of base station. The wireless base station 140 may
have a much larger coverage area than the terrestrial wireless
transceiver 115 or may be a terrestrial transceiver that provides a
coverage area that is of a similar size or of a smaller size than
the coverage area provided by the terrestrial wireless transceiver
115. Wireless base station 140 can be configured to communicate
using one or more wireless communications protocols. While the
example illustrated in FIG. 1 includes on a single wireless base
station 140, in other implementations the network environment is
likely to include more than wireless base station 140 which have
coverage areas that may overlap at least in part.
[0026] The location server 160 can be configured to provide
location services to the mobile device 120. For example, the
location server 160 can be configured to provide almanac
information and/or other information that the mobile device 120 can
use to determine the position of the mobile device 120. The
location server 160 can also be configured to assist the mobile
device 120 in determining the position of the mobile device 120.
For example, the location server 160 can be configured to receive
signal measurements of signals received at the mobile device 120
from wireless transceivers 115 and/or wireless base stations 140
and to determine a position of the mobile device 120 based on those
signals.
[0027] The example network configuration illustrated in FIG. 1 is
merely an example of one possible configuration of a network in
which the techniques disclosed herein may be implemented. Other
network configurations may include additional elements not
illustrated in FIG. 1 and the various components may be
interconnected in a different configuration than what is shown in
FIG. 1.
Example Hardware
[0028] FIG. 2 is a block diagram of a mobile device that can be
used to implement the mobile device 120 illustrated in FIG. 1. The
mobile device 120 can be used to implement, at least in part, the
processes illustrated in FIGS. 6-8.
[0029] The mobile device 120 comprises a computer system including
a general-purpose processor 210, a digital signal processor (DSP)
220, a wireless interface 225, a GNSS interface 265, and a
non-transitory memory 260, connected to each other by a bus 201.
Other implementations of the mobile device 120 may include
additional elements not illustrated in the example implementation
of FIG. 2 and/or may not include all of the elements illustrated in
the example embodiment illustrated in FIG. 2. For example, some
implementations of the mobile device 120 may not include the GNSS
interface 265.
[0030] The wireless interface 225 can include a wireless receiver,
transmitter, transceiver, and/or other elements that enable the
mobile device 120 to send and/or receive data using WWAN, WLAN,
and/or other wireless communication protocols. The wireless
interface 225 can comprise one or more multi-mode modems capable of
transmitting and receiving wireless signals using multiple wireless
communications standards. The wireless interface 225 is connected
by a line 232 to an antenna 234 for sending and receiving
communications to/from the wireless transceivers 115, the wireless
base station 140, and/or other wireless devices configured to
communicate using wireless communication protocols. While the
mobile device 120 illustrated in FIG. 2 comprises a single wireless
interface 225 and a single antenna 234, other implementations of
the mobile device 120 can include multiple wireless interfaces 225
and/or multiple antennas 234.
[0031] The GNSS interface 265 can include a wireless receiver
and/or other elements that enable the mobile device 120 to receive
signals from transmitters associated with one or more GNSS systems.
The GNSS interface 265 is connected by a line 272 to an antenna 274
for receiving signals from the GNSS transmitters, such as the
satellites 170 illustrated in FIG. 1. The mobile device 120 can be
configured to use signals received from satellites and other GNSS
transmitters to determine a position of the mobile device 120. The
mobile device 120 can also be configured to use the signals
received from the satellites and other transmitters associated with
the GNSS systems in conjunction with signals received from wireless
transceivers 115 and/or wireless base stations 140 to determine a
position of the mobile device 120.
[0032] The DSP 220 can be configured to process signals received
from the wireless interface 225 and/or the GNSS interface 265 and
may be configured to process signals for or in conjunction with one
or more modules implemented as processor-readable,
processor-executable software code stored in memory 260 and/or can
be configured process signals in conjunction with the processor
210.
[0033] The processor 210 can be an intelligent device, e.g., a
personal computer central processing unit (CPU) such as those made
by Intel.RTM. Corporation or AMD.RTM., a microcontroller, an
application specific integrated circuit (ASIC), etc. The memory 260
is a non-transitory storage device that can include random access
memory (RAM), read-only memory (ROM), or a combination thereof. The
memory 260 can store processor-readable, processor-executable
software code containing instructions for controlling the processor
210 to perform functions described herein (although the description
may read that the software performs the function(s)). The software
can be loaded onto the memory 260 by being downloaded via a network
connection, uploaded from a disk, etc. Further, the software may
not be directly executable, e.g., requiring compiling before
execution.
[0034] The software in the memory 260 is configured to enable the
processor 210 to perform various actions, including implementing
sending and/or receiving data from the wireless transceivers 115,
the wireless base station 140, other mobile devices 120, and/or
other devices configured for wireless communication.
[0035] FIG. 3 is a functional block diagram of the mobile device
120 illustrated in FIG. 2 that illustrates functional modules of a
memory 260 shown in FIG. 2. For example, the mobile device 120 can
include a position determination module 362, a discovery scan
module 364, and a data access module 366. The mobile device 120 may
also include one or more additional functional modules that provide
other functionality to the mobile device 120. The mobile device 120
illustrated in FIGS. 2 and 3 can be used to implement the mobile
device 120 associated with the processes illustrated in FIGS.
6-8.
[0036] The position determination module 362 can be configured to
determine a position of the mobile device 120. The position
determination module 362 can provide means for determining the
position of the mobile device based at least in part on the signal
measurements. For example, the position determination module 362
can be configured to receive pseudorange data from the GNSS
interface 265 and use the pseudorange data to determine a position
of the mobile device 120. The position determination module 362 can
also be configured to request and receive assistance data from a
network entity, such as the location server 160. The position
determination module 362 can also be configured to use measurements
of signals received from wireless base stations 140 and/or wireless
transceivers 115 to determine a position of the mobile device 120.
The position determination module 362 can also be configured to use
pseudorange information from the GNSS interface 265 and
measurements of signals received from wireless base stations 140
and/or wireless transceivers 115 to determine a position of the
mobile device 120. The position determination module 362 can be
configured to determine the position of the mobile device in
response to a request from an application running on the mobile
device, in response to an external entity (such as the location
server) requesting a position of the mobile device, or in response
to a request from another module of the mobile device. The
processor 210 can also provide means for implementing the various
modules discussed herein and may operate in conjunction.
Furthermore, the wireless interface 225 can provide means for
sending and/or receiving data and/or requests, except for GNSS
signal data for which the GNSS receiver 265 can provide means for
receiving such data.
[0037] The discovery scan module 364 can be configured to perform
active and/or passive scans for wireless transceivers proximate to
the mobile device 120. The discovery scan module 364 can be
configured to identify wireless transceivers 115 proximate to the
mobile device 120 that are configured to receive requests from the
mobile device 120 to perform active and/or passive scans for other
wireless transceivers 115 proximate to the wireless transceivers
115 and to provide the results of the scans to the mobile device
120.
[0038] The discovery scan module 364 can be configured to maintain
a first wireless transceiver list (also referred to herein as a
list of prime transmitters or preferred wireless transceivers list)
and can also be configured to maintain a list of channels
associated with the wireless transceivers on the first wireless
transceiver list. The fires wireless transceiver list can include
wireless transceivers 115 proximate to the mobile device that have
a signal strength over a predetermined threshold. The discovery
scan module 364 can be configured to rank the wireless transceivers
115 based on signal strength of signals received at the mobile
device 120 from each of the wireless transceivers 115 and/or on
other criteria. For example, the discovery scan module 364 can be
configured to rank the wireless transceivers 115 proximate to the
mobile device 120 based on Received Signal Strength Indication
(RSSI) and/or other measurement of the signal strength of signals
received from the wireless transceivers 115 at the mobile device
120. The discovery scan module 364 can be configured to include all
wireless transceivers 115 on the first wireless transceiver list
that have a signal strength measurement that exceeds the
predetermined threshold amount. The discovery scan module 364 can
be configured to limit the size of the first wireless transceiver
list to a predetermined number of wireless transceivers 115. The
discovery scan module 364 can also be configured to maintain the
first wireless transceiver list organized by channel. For example,
the wireless transceivers 115 can be configured to transmit on more
than one frequency band and can be configured to transmit on one or
more channels within the frequency band. The discovery scan module
364 can be configured to maintain the first wireless transceiver
list organized by channel and can be configured to include up to a
predetermined number of wireless transceivers 115 for each channel
on the first wireless transceiver list.
[0039] FIGS. 9A and 9B illustrate how the discovery scan module 364
can be configured to dynamically update the first wireless
transceiver list as the mobile device 120 moves through an indoor
environment. FIG. 9A illustrates the mobile device at a first
position within an indoor environment, and FIG. 9B illustrates the
mobile device at a second position within the indoor environment.
As the mobile device 120 moves from the first position to the
second position the wireless transceivers 115 proximate to the
mobile device 120 can change. For example, at the first position,
the mobile device is proximate to wireless transceivers 115a, 115e,
and 1151, and the discovery scan module 364 selects these three
wireless transceivers from the plurality of wireless transceivers
proximate to the mobile device to be include in the first wireless
transceiver list. As the mobile device 120 moves to the second
position, the discovery scan module 364 can select a new set of
wireless transceivers to include on the first wireless transceiver
list. In this example, at the second position, the wireless
transceivers 115a, 115e, and 1151 have been selected by the
discovery scan module 364. As a mobile device 120 moves through an
indoor environment, different wireless transceivers 115 may be
selected by the discovery scan module 364 for the first wireless
transceiver list using the various techniques discussed above. The
discovery scan module 364 may drop one or more wireless
transceivers from the first wireless transceiver list and/or add
one or more wireless transceivers from the first wireless
transceiver list as the mobile device 120 moves and signal
conditions change due to changing proximity and/or environmental
conditions.
[0040] The discovery scan module 364 can be configured to send a
request to one or more of the wireless transceivers 115 included on
the first wireless transceiver list to perform an active and/or
passive scan for wireless transceivers 115 on behalf of the mobile
device 120. The discovery scan module 364 can be configured to send
the request in the form of a WLAN Radio Measurement frame to the
one or more wireless transceivers 115. The wireless transceivers
115 receiving the request can be configured to perform the
requested active and/or passive scan and to provide the results of
the scan to the mobile device 120. The scan request can specify one
or more channels on which the mobile device 120 is requesting that
the one or more wireless transceivers 115 perform the active and/or
passive scans. The assisted discovery techniques implemented by the
discovery scan module can allow the mobile device 120 to perform a
more extensive scan for wireless transceivers 115 proximate to the
mobile device 120 than may have been possible using conventional
discovery scan techniques in which the mobile device 120 performs
the scans itself. Scanning across multiple channels for signals
from the wireless transceivers 115 can consume significant amounts
of processing resources and wireless interface resources. Scanning
can also consume limited power resources where the mobile device
120 is not receiving power from an external power source and is
instead operating on an internal battery source, such as a
battery.
[0041] A passive scan is a scan across one or more channels in
which wireless transceivers 115 may be operating in which the
discovery scan module 364 or a wireless transceiver 115 performing
a scan on behalf of the mobile device 120 listens for transmissions
from one or more wireless transceivers 115. The transmissions from
the wireless transceivers 115 can be used to identify the wireless
transceiver 115 making the transmission. For example, where a
wireless transceiver 115 is configured to operate using one of the
wireless local area network (WLAN) specifications such as the IEEE
802.11 family of wireless communication protocols, the discovery
scan module 364 or the wireless transceiver 115 performing a scan
on behalf of the mobile device 120 can be configured to listen for
beacons and/or probe responses transmitted by the wireless
transceivers 115 proximate to the mobile device 120 or the wireless
transceiver 115 performing the scan on behalf of the mobile device
120. During a passive scan, the mobile device 120 or the wireless
transceiver 115 performing the scan on behalf of the mobile device
120 does not transmit probe requests or other transmissions to
elicit a response from the wireless transceivers 115 proximate to
the device conducting the passive scan. One risk associated with
passive scanning is that wireless transceivers 115 that do not
broadcast a beacon or other indication of their presence could be
missed by the device conducting the passive scan.
[0042] An active scan is a scan across one or more channels in
which wireless transceivers 115 may be operating in which the
discovery scan module 364 or a wireless transceiver 115 performing
a scan on behalf of the mobile device 120 actively solicits
wireless transceivers 115 for responses in addition to listening
for transmissions from one or more wireless transceivers 115. A
device conducting an active scan can be configured to transmit
probe requests that include a null SSID name (a probe-any request)
to solicit responses from all wireless transceivers 115 configured
to receive and respond to such probe requests. Active scanning can
consume more power than passive scans because the device conducting
the scan is transmitting requests as well as listening for beacons
and/or probe request responses from wireless transceivers 115
proximate to the device conducting the active scan.
[0043] The discovery scan module 364 can be configured to perform a
passive scan for one or more wireless transceiver 115 proximate to
the mobile device and to send a request to the one or more wireless
transceivers 115 proximate to the mobile device to conduct an
passive and/or active scan for other wireless transceivers 115 on
behalf of the mobile device 120. This assisted discovery approach
can consume less power and processing resources on the mobile
device 120, which may have a limited power supply provided by a
battery and may have limited processing power in order to reduce
power consumption and extend battery life. The assisted discovery
approach can also speed up the discovery process, because the
mobile device 120 can request that multiple wireless transceivers
115 perform discovery scans in parallel with one another. The
discovery scan module 364 can also be configured to perform scans
in parallel with one or more wireless transceivers 115 in order to
obtain scan results quicker than would be possible if the mobile
device 120 performed similar scans.
[0044] The discovery scan module 364 can be configured to process
scan reports provided by wireless transceivers 115 and to update
information that identifies wireless transceivers proximate to the
mobile device 120. The wireless transceiver information can be
stored in the memory 260 and can be accessed and/or updated by the
discovery scan module 364 via the data access module 366. The
position determination module 362 can be configured to use the
wireless transceiver information to determine the location of the
mobile device. For example, the position determination module 362
can be configured to select wireless transceivers 115 from the list
of wireless transceivers 115 proximate to the mobile device 120 and
to take signal measurements that the position determination module
362 can use to determine a position of the mobile device 120. The
position determination module 362 can also be configured to send
the signal measurements to a location server or other network
entity that is configured to determine the position of the mobile
device and/or provide assistance data to the mobile device 120 that
the mobile device 120 can use to determine the position of the
mobile device 120.
[0045] The discovery scan module 364 can also be configured to
perform location context identifier (LCI) disambiguation using the
technique illustrated in FIG. 8. The position determination module
362 may, under some circumstances, be unable to determine whether
the mobile device 120 is located in a portion of an indoor
environment associated with a first LCI or a second LCI. In some
situations, that position determination module 362 may need to
disambiguate between more than two LCIs. The position determination
module 362 can be configured to send a request to the discovery
scan module 364 to perform an LCI disambiguation using the assisted
discovery techniques disclosed herein. The discovery scan module
364 can be configured to use an assisted scanning technique to
obtain information identifying wireless transceivers 115 proximate
to the mobile device 120, and the discovery scan module 364 can be
configured to conduct a scan for wireless transceivers 115
proximate to the mobile device 120. The discovery scan module 364
can be configured to compare the results obtained from the assisted
scan with the results obtained from the scan conducted by the
mobile device 120 in an attempt to disambiguate which LCI the
mobile device is associated.
[0046] The data access module 366 can be configured to store data
in the memory 260 and/or other data storage devices associated with
the mobile device 120. The data access module 366 can also be
configured to access data in the memory 260 and/or other data
storage devices associated with the mobile device 120. The data
access module 366 can be configured to receive requests from other
modules and/or components of the mobile device 120 and to store
and/or access data stored in the memory 260 and/or other data
storage devices associated with the mobile device 120.
[0047] The discovery scan module 364 in conjunction with the
wireless interface 225 can provide means for performing a passive
scan for wireless transceivers proximate to the mobile device to
generate passive scan results. The discovery scan module 364 can
provide means for generating a first wireless transceiver list,
comprising a first set of wireless transceivers. The discovery scan
module 364 in conjunction with the wireless interface 225 can
provide means for transmitting a request to at least one wireless
transceiver from the first wireless transceiver list requesting
that the at least one wireless transceiver perform a scan for
wireless transceivers and means for receiving scan results from the
at least one wireless transceiver from the first wireless
transceiver list. The discovery scan module 364 can provide means
for generating a second wireless transceiver list comprising
identifying information for a second set of wireless transceivers,
proximate to the at least one wireless transceiver. The discovery
scan module 364 in conjunction with the wireless interface 225 can
provide means for measuring signals received from wireless
transceivers selected from the first wireless transceiver list, or
the second wireless transceiver list, or combination thereof. The
discovery scan module 364 and/or the position determination module
362 can provide means for determining the position of the mobile
device based at least in part on the signals measured. The
discovery scan module 364 can also provide means for periodically
performing additional passive scans for the wireless transceivers
proximate to the mobile device and means for updating the first
wireless transceiver list based on results of the additional
passive scans. The means for updating the first wireless
transceiver list provided by the discovery scan module 364 can
include means for removing one or more wireless transceivers from
the first wireless transceiver list responsive to a signal strength
associated with each of the one or more wireless transceivers from
the first wireless transceiver list falling below a first
predetermined threshold. The means for updating the first wireless
transceiver list provided by the discovery scan module 364 can
include means for adding one or more wireless transceivers that are
currently not on the first wireless transceiver list to the first
wireless transceiver list responsive to the signal strength
associated with each of the one or more wireless transceivers that
are currently not on the first wireless transceiver list exceeding
a second predetermined threshold.
[0048] The discovery scan module 364 can also provide means for
performing a scan for wireless transceivers proximate to the mobile
device to generate discovery scan results from the scan for
wireless transceivers proximate to the mobile device and means for
generating a first wireless transceiver list based on the discovery
scan results from the scan for wireless transceivers proximate to
the mobile device, where the first wireless transceiver list
includes a first subset of the wireless transceivers proximate to
the mobile device, and where the wireless transceivers in the first
subset of the wireless transceivers proximate to the mobile device
are associated with a first location context identifier (LCI) with
which the mobile device is associated. The discovery scan module
364 can also provide means for generating a second wireless
transceiver list based on the first discovery scan results, where
the second wireless transceiver list includes a second subset of
the wireless transceivers proximate to the mobile device, and where
the wireless transceivers in the second subset of the wireless
transceivers proximate to the mobile device are associated with a
second LCI that is different from the first LCI. The discovery scan
module 364 in conjunction with the wireless interface 225 can also
provide means for transmitting a first scan request to at least one
wireless transceiver from the first wireless transceiver list
requesting the at least one wireless transceiver from the first
wireless transceiver list perform a scan for wireless transmitters
proximate to the at least one wireless transceiver from the first
wireless transceiver list and means for transmitting a second scan
request to at least one wireless transceiver from the second
wireless transceiver list requesting the at least one wireless
transceiver from the second wireless transceiver list perform a
discovery scan for wireless transmitters proximate to the at least
one wireless transceiver from the second wireless transceiver list.
The discovery scan module 364 in conjunction with the wireless
interface 225 can also provide means for receiving discovery scan
results from the at least one wireless transceiver from the first
wireless transceiver list and means for receiving discovery scan
results from the at least one wireless transceiver from the second
wireless transceiver list. The discovery scan module 364 can also
provide means for comparing the discovery scan results from the
scan for wireless transceivers proximate to the mobile device with
the discovery scan results from the at least one wireless
transceiver from the first wireless transceiver list and the
discovery scan results from the at least one wireless transceiver
from the second wireless transceiver list. The discovery scan
module 364 and/or the position determination module 362 can also
provide means for determining an LCI associated with a portion of
an indoor environment in which the mobile device is located based
at least in part on results of comparison. The first scan request,
the second scan request, or both can be a request to perform an
active scan or a passive scan. The discovery scan module 364 can
also provide means for selecting the LCI from a plurality of LCIs
based on a number of wireless transceivers included in the
discovery scan results also appearing in the discovery scan results
associated with the LCI that is selected. The discovery scan module
364 can also provide means for determining an LCI associated with a
portion of an indoor environment in which the mobile device is
located based at least in part on results of comparison further
comprises selecting the LCI based on a number of wireless
transceivers included in the discovery scan results from the scan
for wireless transceivers proximate to the mobile device, the
discovery scan results from the at least one wireless transceiver
from the first wireless transceiver list, and the discovery scan
results from the at least one wireless transceiver from the second
wireless transceiver list associated with the LCI. The discovery
scan module 364 can provide means for selecting the LCI based on a
number of wireless transceivers included in the discovery scan
results conducted by the wireless transceiver that were included in
the discovery scan results from the at least one wireless
transceiver from the first wireless transceiver list, which
includes wireless transceivers associated with the current LCI with
which the mobile device 120 is associated, and based on a number of
wireless transceivers included in the discovery scan results
conducted by the wireless transceiver that were included in the
discovery scan results from the at least one wireless transceiver
from the second wireless transceiver list, which includes wireless
transceivers not associated with the current LCI with which the
mobile device 120 is associated. If more wireless transceivers
identified by the scan conducted by the mobile device match those
associated with the current LCI, the discovery scan module can be
configured to continue associating the current LCI with the mobile
device 120. Otherwise, the discovery scan module can be configured
to associate a new LCI based on a number of matches of wireless
transceivers included in the discovery scan result conducted by the
mobile device 120 and discovery scan results associated with
wireless transceivers included in the second wireless transceiver
list.
[0049] FIG. 4 is a block diagram of a wireless transceiver that can
be used to implement the wireless transceivers 115 illustrated in
FIG. 1. The wireless transceiver 115 can be used to implement, at
least in part, the processes illustrated in FIGS. 6-8.
[0050] The wireless transceiver 115 comprises a computer system
including a general-purpose processor 410, a digital signal
processor (DSP) 420, a wireless interface 425, a wired network
interface 465, and a non-transitory memory 460, connected to each
other by a bus 401. Other implementations of the wireless
transceiver 115 may include additional elements not illustrated in
the example implementation of FIG. 4 and/or may not include all of
the elements illustrated in the example embodiment illustrated in
FIG. 4. For example, some implementations of the wireless
transceiver 115 may not include the wired network interface
465.
[0051] The wireless interface 425 can include a wireless receiver,
transmitter, transceiver, and/or other elements that enable the
wireless interface 425 to send and/or receive data using WWAN,
WLAN, and/or other wireless communication protocols. The wireless
interface 425 can comprise one or more multi-mode modems capable of
transmitting and receiving wireless signals using multiple wireless
communications standards. The wireless interface 425 is connected
by a line 432 to an antenna 434 for sending and receiving
communications to/from the mobile device 120, the wireless base
station 140, and/or other wireless devices configured to
communicate using wireless communication protocols. While the
wireless transceiver 115 illustrated in FIG. 4 comprises a single
wireless interface 425 and a single antenna 434, other
implementations of the wireless transceiver 115 can include
multiple wireless interfaces 425 and/or multiple antennas 434. In
some implementations, the wireless transceiver 115 can be
configured to provide wireless network access to the mobile device
120 and/or other wireless devices. For example, the wireless
transceiver 115 can be configured to operate as a WLAN access point
that can provide wireless connectivity to the mobile device 120
and/or other devices configured to communicate using WLAN wireless
communication protocols. In some implementations, the wireless
transceiver 115 can be configured to provide network connectivity
to the mobile device 120 using a first wireless protocol and to
connect to the Internet or other network via a second wireless
protocol. For example, the wireless transceiver 115 can be
configured to connect to the network 110 via a WWAN wireless
communication protocol and to connect to the mobile device 120
using a WLAN wireless communication protocol.
[0052] The wireless transceiver 115 can also include wired network
interface 465 that provides wired network connectivity to the
network 110. For example, the wired network connection can comprise
a wired broadband connection, and the wired network interface 465
can be configured to comprise or connect to a cable modem and/or a
Digital Subscriber Line (DSL) modem. The wired network interface
465 can be configured to send and/or receive data via the wired
network connection.
[0053] The DSP 420 can be configured to process signals received
from the wireless interface 425 and/or the wired network interface
465 and may be configured to process signals for or in conjunction
with one or more modules implemented as processor-readable,
processor-executable software code stored in memory 460 and/or can
be configured process signals in conjunction with the processor
410.
[0054] The processor 410 can be an intelligent device, e.g., a
personal computer central processing unit (CPU) such as those made
by Intel.RTM. Corporation or AMD.RTM., a microcontroller, an
application specific integrated circuit (ASIC), etc. The memory 460
is a non-transitory storage device that can include random access
memory (RAM), read-only memory (ROM), or a combination thereof. The
memory 460 can store processor-readable, processor-executable
software code containing instructions for controlling the processor
410 to perform functions described herein (although the description
may read that the software performs the function(s)). The software
can be loaded onto the memory 460 by being downloaded via a network
connection, uploaded from a disk, etc. Further, the software may
not be directly executable, e.g., requiring compiling before
execution.
[0055] The software in the memory 460 is configured to enable the
processor 410 to perform various actions, including implementing
sending and/or receiving data from the mobile device 120, and/or
other devices configured for wireless communication.
[0056] FIG. 5 is a functional block diagram of the wireless
transceiver 115 illustrated in FIG. 4 that illustrates functional
modules of a memory 460 shown in FIG. 4. For example, the wireless
transceiver 115 can include a discovery scan module 562, and a data
access module 566. The wireless transceiver 115 may also include
one or more additional functional modules that provide other
functionality to the wireless transceiver 115. The wireless
transceiver 115 illustrated in FIGS. 4 and 5 can be used to
implement the wireless transceiver 115 associated with the
processes illustrated in FIGS. 6-8.
[0057] The discovery scan module 562 can be configured to receive
requests to perform scans for wireless transceivers proximate to
the wireless transceiver 115 from the mobile device 120. The
discovery scan module 562 can be configured to wirelessly receive
the request from the mobile device 120. In some implementations,
the request from the mobile device 120 can be in the form of a WLAN
Radio Measurement frame. The request can specify a scan type to be
performed and the discovery scan module 562 can be configured to
operate the wireless interface 425 to scan for other wireless
transceivers proximate to the wireless transceiver 115 according to
the parameters defined in the request. For example, the request can
specify whether an active or a passive scan is being requested. The
discovery scan module 562 can perform the requested active and/or
passive scan and can transmit the results of the scan to the mobile
device 120 via the wireless connection between the wireless
transceiver 115 and the mobile device 120. The discovery scan
module 562 can be configured to perform the scan for other wireless
transceivers on multiple channels. The scan request can specify one
or more channels on which the wireless transceiver 115 is to
perform the active and/or passive scans.
[0058] The data access module 566 can be configured to store data
in the memory 460 and/or other data storage devices associated with
the wireless transceiver 115. The data access module 566 can also
be configured to access data in the memory 460 and/or other data
storage devices associated with the wireless transceiver 115. The
data access module 566 can be configured to receive requests from
other modules and/or components of the wireless transceiver 115 and
to store and/or access data stored in the memory 460 and/or other
data storage devices associated with the wireless transceiver
115.
Example Implementations
[0059] FIG. 6 is a flow diagram of a process for determining the
position of a mobile device 120 using the passive scanning
techniques discussed herein. The process illustrated in FIG. 6 can
be implemented using the mobile device 120 illustrated in FIG. 1.
The discovery scan module 364 of the mobile device 120 provides
means for performing the various stages included in the process
illustrated in FIG. 6 unless otherwise specified.
[0060] A passive scan for wireless transceivers proximate to the
mobile device 120 can be performed to generate passive scan results
(stage 605). The discovery scan module 364 of the mobile device 120
can be configured to perform a passive scan for a first set of
wireless transceivers proximate to the mobile device 120. The
discovery scan module 364 can be configured to operate the wireless
interface 225 of the mobile device 120 to detect signals from one
or more wireless transceivers 115 proximate to the mobile device
120. The discovery scan module 364 can be configured to conduct the
passive scan across one or more channels. The area in which the
mobile device 120 is located may include multiple wireless
transceivers 115 and these wireless transceivers may be operating
on more than one channel. The discovery scan module 364 can be
configured to access channel information that indicates which
channels the wireless transceivers 115 are most likely to be
operating on in the area which the mobile device 120 is located.
The discovery scan module 364 can be configured to obtain a coarse
position estimate from the position determination module 362 which
the discovery scan module 364 can use to select channel information
appropriate for the geographic area in which the mobile device is
located. The position determination module 362 can also be
configured to provide a coarse position estimate based on
previously determined position information for the mobile device
120. The channel information can be stored in the memory 260 of the
mobile device 120. The discovery scan module 364 can also be
configured to obtain the channel information from the location
server 160 or another network entity. In some implementations, the
channel information may be provided by a mobile network carrier
associated with the mobile device 120 at the time that the mobile
device is configured to operate with the mobile network carrier's
network.
[0061] When conducting the passive scan, the discovery scan module
364 can be configured to operate the wireless interface 225 to
listen for transmissions from wireless transceivers 115 proximate
to the mobile device 120. For example, the discovery scan module
364 can be configured to operate the wireless interface 225 to
listen for beacons and/or probe responses where at least a portion
of the wireless transceivers 115 comprise WLAN wireless access
points. The discovery scan module 364 can be configured to use the
beacons, probe responses, and/or other signals transmitted by the
wireless transceivers 115 to identify the wireless transceivers 115
transmitting the information. The discovery scan module 364 can
also be configured to measure signal strength of the signals
received from each of the wireless transceivers 115. For example,
the discovery scan module 364 can be configured to measure the
signal strength of signals received from the wireless transceivers
115 proximate to the mobile device 120 and to associate Received
Signal Strength Indicator (RSSI) values with each of the wireless
transceivers 115 from which signals were received.
[0062] A first wireless transceiver list that includes a first set
of wireless transceivers can be generated based on the passive scan
results (stage 610). The discovery scan module 364 can be
configured to generate a first wireless transceiver list based on
the results of the passive scan. The discovery scan module 364 can
be configured to select one or more wireless transceivers 115 to
add to the first wireless transceiver list based on signal
measurements. For example, the discovery scan module 364 can be
configured to rank the wireless transceivers 115 from which signals
were received by a signal strength value associated with each of
the wireless transceivers 115. The discovery scan module 364 can be
configured to select up to a predetermined number of wireless
transceivers 115 to include on the first wireless transceiver list.
The discovery scan module 364 can also be configured to include all
of the wireless transceivers 115 from which signals were
received.
[0063] A request can be transmitted to at least one wireless
transceiver from the first wireless transceiver list requesting
that the at least one wireless transceiver perform a scan (stage
615). The discovery scan module 364 can be configured to select one
or more of the wireless transceivers from the first wireless
transceiver list and send a request to the each of the selected
wireless transceivers 115 to perform a scan for other wireless
transceivers 115 on behalf of the mobile device 120. The discovery
scan module 364 can be configured to send the request to the
selected wireless transceiver or wireless transceivers 115 in the
form of a WLAN Radio Measurement frame. The request can specify a
scan type to be performed. For example, the request can specify
whether an active or a passive scan is being requested. The
wireless transceivers 115 receiving the request can be configured
to perform the requested active and/or passive scan and to provide
the results of the scan to the mobile device 120. The scan request
can specify one or more channels on which the mobile device 120 is
requesting that the one or more wireless transceivers 115 perform
the active and/or passive scans. The discovery scan module 364 can
be configured to select multiple wireless transceivers 115 to
perform multiple scans in parallel with one another. The scans can
be conducted on multiple channels at once and can significantly
decrease the amount of time that would be required to conduct a
discovery scan. Furthermore, the discovery scans conducted by the
wireless transceivers 115 may also be more accurate, as the
wireless transceivers typically operate a higher transmit and
receive power than the mobile device 120 and thus be more sensitive
than the mobile device 120 providing more accurate results.
Furthermore, wireless transceivers 115 that have switched to a
different channel or those do not broadcast an SSID or other
identifier may also be detected more quickly as the discovery scan
can be conducted across multiple channels at once by the wireless
transceivers 115.
[0064] Scan results can be received from the at least one wireless
transceiver from the first wireless transceiver list (stage 617).
The discovery scan module 364 can be configured to receive
discovery scan results via the wireless interface 225 of the mobile
device 120. The discovery scan results from the at least one
wireless transceiver 115 from the first wireless transceiver list
can include information that identifies one or more other wireless
transceivers 115 proximate to at least one wireless transceiver 115
from the first wireless transceiver list. In some implementations,
the scan results comprise one or more WLAN Radio Measurement Report
frames. The scan results can include information such as the
channel set and/or channel number for which the scan results apply,
measurement start and end times and/or measurement duration, and
information identifying one or more wireless transceivers 115 from
which signals were received during the scan. The scan results can
also identify whether a passive or active scan was performed by the
wireless transceiver 115 that conducted the scan.
[0065] A second wireless transceiver list comprising identifying
information for a second set of wireless transceivers proximate to
the at least one wireless transceiver from the first wireless
transceiver list can be generated based on the scan results (stage
620). The discovery scan module 364 can be configured to generate
the second wireless transceiver list based on the scan results
received from the at least one wireless transceiver from the first
wireless transceiver list. The discovery scan module 364 can be
configured to include all of the wireless transceivers included in
the scan results in the second wireless transceiver list. The
discovery scan module 364 can also be configured to select a subset
of the wireless transceivers included in the scan results to
include in the second wireless transceiver list. For example, the
discovery scan module 364 can be configured to select a subset of
wireless transceivers 115 the scan results provided each of the
wireless transceivers 115 from the first wireless transceiver list
115 from which scan results are received. The discovery scan module
364 can also be configured to select wireless transceivers 115 that
are included in the scan results received from multiple wireless
transceivers 115 from the first wireless transceiver list, because
the selected wireless transceivers 115 are likely to be proximate
to the mobile device 120.
[0066] Signals received from wireless transceivers from the first
wireless transceiver list, the second wireless transceiver list, or
a combination thereof can be measured to generate signal
measurements (stage 625). In some implementations, the discovery
scan module 364 can be configured to select all of the wireless
transceivers from the first wireless transceiver list and the
second wireless transceiver list and to collect signal measurements
from those wireless transceivers 115 via the wireless interface 225
of the mobile device 120. The discovery scan module 364 can also be
configured to select a subset of the wireless transceivers 115 from
the first wireless transceiver list and/or the second wireless
transceiver list from which signal measurements will be collected.
For example, the discovery scan module 364 can be configured to
obtain signal strength measurements, such as RSSI (received signal
strength indication) measurements, timing measurements, such as RTT
(round-trip time)) and/or time of arrival (TOA) measurements, or a
combination thereof from the wireless transceivers from the first
wireless transceiver list, the second wireless transceiver list, or
a combination thereof can be measured to generate the signal
measurements.
[0067] A position of the mobile device can be determined based at
least in part on the signals measured (stage 630). The position
determination module 362 can be configured to determine a position
of the mobile device based on measurements of signals received from
the selected wireless transceivers 115. For example, the position
determination module 362 can be configured to determine a position
of the mobile device 120 by performing trilateration using signal
measurements. The position determination module 362 can be
configured to use timing measurements and/or signal strength
measurements to determine an estimate range from the wireless
transceivers 115 from which the signal measurements have been
obtained, and the position determination module 362 can use this
information to determine an estimated position of the mobile device
120. The position determination module 362 can be configured to
make use of GNSS information as well as the signal measurements
obtained from the selected wireless transceivers to determine a
position of the mobile device 120. For example, the GNSS receiver
265 of the mobile device may have obtained pseudorange measurements
for one or more GNSS satellites but has obtained an insufficient
number of pseudorange measurements to determine a position of the
mobile device. However, the position determination module 362 can
be configured to use the pseudorange measurements in addition to
other information, such as the signal measurements from the
selected wireless transceivers 115 to determine a position of the
mobile device 120. The position determination module 362 can also
be configured to send the signal measurements, range information
derived therefrom, and/or pseudorange measurements to the location
server 160, and the location server 160 can be configured to
determine the position of the mobile device 120 and to send
position information to the mobile device 120.
[0068] FIG. 7 is a flow diagram of a process for providing
assistance data to a mobile device according. The process
illustrated in FIG. 7 can be implemented by a wireless transceiver
115, such as those illustrated in FIG. 1. The process illustrated
in FIG. 7 can be used by the wireless transceiver to perform a scan
in response to receiving a request to perform a scan from a mobile
device 120 and to provide the scan results to the mobile device
120.
[0069] A request to perform one or more scans for other wireless
transceivers 115 proximate to the wireless transceiver 115 can be
received (stage 705). The wireless transceiver 115 can receive the
request from the mobile device 120 via a wireless connection
between the wireless transceiver 115 and the mobile device 120. The
request from the mobile device 120 can comprise a WLAN Radio
Measurement frame that includes parameters that scan type to be
performed and/or on which channels the discovery scan module 562 of
the wireless transceiver 115 should scan for other wireless
transceivers 115. For example, the request can specify whether an
active or a passive scan is being requested.
[0070] The scan or scans can be performed according to the request
parameters (stage 710). The request received from the mobile device
120 request that one or more active and/or passive scans be
performed on behalf of the mobile device 120. The discovery scan
module 562 can be configured to operate the wireless interface 425
of the wireless transceiver 115 to perform the requested scan or
scans and to collect the results of the scans. The scan request can
specify one or more channels on which the discovery scans are to be
performed, and the discovery scan module 562 can conduct the scan
or scans on the specified channels.
[0071] The scan results including information identifying the other
wireless transceivers proximate to the wireless transceiver
identified during the scan or scans performed by the wireless
transceiver can be transmitted to the mobile device (stage 715).
The discovery scan module 562 of the wireless transceiver 115 can
be configured to send the scan results to the mobile device 120
requesting the scan results via the wireless interface 425. In some
implementations, the scan results can be transmitted in the form of
a WLAN Radio Measurement Report frame. The scan results can include
an identifier that identifies which wireless transceiver 115
conducted a scan and is providing scan results. The scan results
can include information such as the channel set and/or channel
number for which the scan results apply, measurement start and end
times and/or measurement duration, and information identifying one
or more wireless transceivers 115 from which signals were received
during the scan. The scan results can also identify whether a
passive or active scan was performed by the wireless transceiver
115 that conducted the scan.
LCI Disambiguation
[0072] One or more local coordinate systems can be established for
an indoor environment to facilitate providing location-based
services related to that indoor environment. An indoor environment
can be associated with a "location context" and a location server
may store associate one or more location context identifiers (LCIs)
with the location context. Each LCI can be associated with
locally-defined areas of the indoor environment associated with the
location context. For example, each floor of an indoor environment
may be associated with a different LCI. An LCI is not limited to
defining a floor of an indoor environment and may also be
associated with other portions of the indoor environment. The floor
of a building or other portion of an indoor environment may be
mapped according to a local coordinate system rather than a global
coordinate system, and this information can be associated with the
LCI associated with the floor or other portion of the indoor
environment.
[0073] An LCI can be associated with information that can be used
to assist in determining the position of the mobile device 120. For
example, a particular LCI may be associated with maps of the floor
or other portion of the indoor environment associated with the LCI.
The map information can comprise schematic maps of the floor or
other portion of the indoor environment and/or graphs or maps of
routes through the floor or other portion of the indoor
environment. The map information may also include information that
identifies points of interest within the area of the indoor
environment represented by the LCI. The map information can include
information identifying the position of one or more wireless
transceivers 115 within the floor or other portion of the indoor
environment associated with the LCI. The map information can also
include heatmaps or other representations of measured and/or
estimated signal strengths of signals from one or more wireless
transceivers 115 disposed throughout the indoor environment from
one or more as measured from one or more locations within the area
associated with the LCI.
[0074] The position determination module 362 can be configured to
receive assistance from the location server 160 to determine the
location and/or the LCI based on signal measurements obtained by
the mobile device 120. In some instance, the position determination
module, with our without assistance from the location server 160,
can obtain signal measurements from wireless transceivers 115
disposed throughout an indoor environment and the measurements are
ambiguous as to which LCI is associated with the current position
of the mobile device 120 within the indoor environment.
[0075] The techniques illustrated in FIG. 8 can be used to help
disambiguate which LCI the mobile device 120 should be associated
with. In particular, the technique discussed herein can be useful
when moving between LCIs. For example, the technique illustrated in
FIG. 8 may be used to determine whether the mobile device 120 has
moved from a LCI associated with a first floor of an indoor
environment to an LCI associated with a second floor of an indoor
environment. The mobile device 120 can then use this information to
obtain maps or other information associated with the appropriate
LCI that can be used to for position-based and/or navigation
services. The technique illustrated in FIG. 8 may provide more
accurate LCI disambiguation compared to conventional techniques for
LCI disambiguation which may only take into account signal strength
from wireless transceivers 115 proximate to the mobile device 120.
However, some wireless transceivers 115 may have a higher gain and
reflections of signals within the local environment may also
interfere with such conventional techniques. Movement of the mobile
device 120 and the environment in which the mobile device 120 is
operating can also affect the signals measurements obtained from
wireless transceivers 115 proximate to the mobile device. For
example, the orientation of the mobile device relative to the
wireless transceiver 115 can affect the signal strength
measurements. Occlusion of the signals by the body of a user of the
mobile device 120 can also affect the signal strength measurements.
Environmental features, such as furniture and/or equipment in the
indoor environment and structural elements of the indoor
environment, such as walls and doors, can affect the signal
measurements obtained at the mobile device 120. Furthermore,
interference from other devices operating within the indoor
environment can also affect the signal measurements obtained by the
mobile device 120. These and other factors can impact the quality
of signal measurements obtained by the mobile device 120.
[0076] FIG. 8 is a flow diagram of a process for disambiguation
that can make use of the active and/or passive scanning techniques
discussed herein. The position determination module 362 can be
configured to determine which LCI is associated with a portion of
an indoor environment in which the mobile device 120 is located by
conducting a discovery scan and then comparing the results of the
discovery scan with the results of a discovery scan conducted by
one or more wireless transceivers 115 proximate to the mobile
device 120. The process illustrated in FIG. 8 can be used to
disambiguate which LCI is associated with the current position of
the mobile device. The process illustrated in FIG. 8 can be
performed by the mobile device 120. The discovery scan module 364
of the mobile device 120 provides means for performing the various
stages included in the process illustrated in FIG. 8 unless
otherwise specified.
[0077] A scan for wireless transceivers proximate to the mobile
device 120 can be performed to generate discovery scan results from
the scan for wireless transceivers proximate to the mobile device
(stage 805). The discovery scan module 364 of the mobile device 120
can be configured to perform either an active or a passive scan for
wireless transceivers proximate to the mobile device 120. The
discovery scan module 364 can be configured to operate the wireless
interface 225 of the mobile device 120 to detect signals from one
or more wireless transceivers 115 proximate to the mobile device
120. The discovery scan module 364 can be configured to conduct the
discovery scan across one or more channels. The area in which the
mobile device 120 is located may include multiple wireless
transceivers 115 and these wireless transceivers may be operating
on more than one channel. The discovery scan module 364 can be
configured to access channel information that indicates which
channels the wireless transceivers 115 are most likely to be
operating on in the area which the mobile device 120 is located.
The discovery scan module 364 can be configured to obtain a coarse
position estimate from the position determination module 362 which
the discovery scan module 364 can use to select channel information
appropriate for the geographic area in which the mobile device is
located. The position determination module 362 can also be
configured to provide a coarse position estimate based on
previously determined position information for the mobile device
120. The channel information can be stored in the memory 260 of the
mobile device 120. The discovery scan module 364 can also be
configured to obtain the channel information from the location
server 160 or another network entity. In some implementations, the
channel information may be provided by a mobile network carrier
associated with the mobile device 120 at the time that the mobile
device is configured to operate with the mobile network carrier's
network.
[0078] When conducting a passive scan, the discovery scan module
364 can be configured to operate the wireless interface 225 to
listen for transmissions from wireless transceivers 115 proximate
to the mobile device 120. For example, the discovery scan module
364 can be configured to operate the wireless interface 225 to
listen for beacons and/or probe responses where at least a portion
of the wireless transceivers 115 comprise WLAN wireless access
points. The discovery scan module 364 can be configured to use the
beacons, probe responses, and/or other signals transmitted by the
wireless transceivers 115 to identify the wireless transceivers 115
transmitting the information. The discovery scan module 364 can
also be configured to measure signal strength of the signals
received from each of the wireless transceivers 115. For example,
the discovery scan module 364 can be configured to measure the
signal strength of signals received from the wireless transceivers
115 proximate to the mobile device 120 and to associate Received
Signal Strength Indicator (RSSI) values with each of the wireless
transceivers 115 from which signals were received. When conducting
an active discovery scan, the discovery scan module 364 can be
configured to operate the wireless interface 225 to transmit probe
requests that include a null SSID name (a probe-any request) to
solicit responses from all wireless transceivers 115 configured to
receive and respond to such probe requests.
[0079] A first wireless transceiver list can be generated based on
the discovery scan results from the scan for wireless transceivers
proximate to the mobile device, the first wireless transceiver list
comprising a first subset of the wireless transceivers proximate to
the mobile device, where the wireless transceivers in the first
subset of the wireless transceivers proximate to the mobile device
are associated with a first location context identifier (LCI) with
which the mobile device is associated (stage 810). The discovery
scan module 364 can be configured to generate the first wireless
transceiver list based on the results of the discovery scan
performed by the mobile device 120 which includes a subset of the
wireless transceivers proximate to the mobile device and associated
with a first LCI with which the mobile device is associated. The
discovery scan module 364 can be configured to select one or more
wireless transceivers 115 to add to the first wireless transceiver
list based on signal measurements. For example, the discovery scan
module 364 can be configured to rank the wireless transceivers 115
from which signals were received by the signal strength value
associated with each of the wireless transceivers 115. The
discovery scan module 364 can be configured to select up to a
predetermined number of wireless transceivers 115 to include on the
first wireless transceiver list. The discovery scan module 364 can
also be configured to include all of the wireless transceivers 115
from which signals were received. In implementations where the
discovery scan was an active scan, the discovery scan module 364
can be configured to obtain signal measurements of signals from
each of the wireless transceivers 115 from which responses to the
probe request were received. For example, the discovery scan module
364 can be configured to use signal measurements such as RSSI
(received signal strength indication), RTT (round-trip time)), and
time of arrival (TOA) measurements to rank the wireless
transceivers 115. In some implementations, the discovery scan
module 364 may already have created a first wireless transceiver
list and the discovery scan module 364 can be configured to update
the existing list based on the first discovery scan results
resulting from the discovery scan conducted in stage 805.
[0080] A second wireless transceiver list can be generated based on
the discovery scan results from the scan for wireless transceivers
115 proximate to the mobile device 120, the second wireless
transceiver list comprising a second subset of the wireless
transceivers 115 proximate to the mobile device 120, where the
wireless transceivers in the second subset of the wireless
transceivers proximate to the mobile device are associated with a
second LCI, wherein the second LCI is different from the first LCI
(stage 815). The second wireless transceiver list includes a subset
of the wireless transceivers proximate to the mobile device (as
determined by the discovery scan conducted by the mobile device
120) and associated with a second LCI which is different than the
first LCI with which the mobile device 120 is associated. In some
implementations, the second wireless transceiver list can include
subsets of wireless transceivers 115 that are each associated with
more than one LCI that is different than the first LCI with which
the mobile device 120 is associated. The discovery scan module 364
can be configured to generate the second wireless transceiver list
based on the results of the discovery scan. The discovery scan
module 364 can be configured to compare LCI information associated
with each of the wireless transceivers 115 detected in the
discovery scan with the first LCI currently associated with the
mobile device 120 and to add the wireless transceivers 115
associated with a different LCI than the current LCI to the second
wireless transceiver list. The discovery scan module 364 can use
this information to determine whether the mobile device 120 is
located in a portion of the indoor environment associated with a
first LCI in which the mobile device 120 is currently believed to
be located or is actually located in another LCI associated with
the one or more wireless transceivers 115 associated with a
different LCI.
[0081] A first scan request can be transmitted to at least one
wireless transceiver from first wireless transceiver list
requesting the at least one wireless transceiver from the first
wireless transceiver list perform a scan for wireless transmitters
proximate to the at least one wireless transceiver from the first
wireless transceiver list (stage 820), and a second scan request
can be transmitted to at least one wireless transceiver from the
second wireless transceiver list requesting the at least one
wireless transceiver from the second wireless transceiver list
perform a discovery scan for wireless transmitters proximate to the
at least one wireless transceiver from the second wireless (stage
825). The discovery scan module 364 can be configured to select one
or more of the wireless transceivers from the first wireless
transceiver list and at least one wireless transceiver from the
second wireless transceiver list and send a scan request to the
each of the selected wireless transceivers 115 to perform a scan
for other wireless transceivers 115 on behalf of the mobile device
120. The discovery scan module 364 can be configured to send the
request to the selected wireless transceiver or transceivers 115
from each list in the form of a WLAN Radio Measurement frame. The
request can also specify a scan type to be performed. For example,
the request can specify whether an active or a passive scan is
being requested. The wireless transceivers 115 receiving the
request can be configured to perform the requested active and/or
passive scan and to provide the results of the scan to the mobile
device 120. The scan request can specify one or more channels on
which the mobile device 120 is requesting that the one or more
wireless transceivers 115 perform the active and/or passive scans.
The discovery scan module 364 can be configured to send the request
to the selected wireless transceiver or transceivers 115 from each
list in the form of a WLAN Radio Measurement frame. The scan
request can specify one or more channels on which the mobile device
120 is requesting that the one or more wireless transceivers 115
perform the active and/or passive scans. The discovery scan module
364 can be configured to select multiple wireless transceivers 115
to perform multiple scans in parallel with one another. The scans
can be conducted on multiple channels at once and can significantly
decrease the amount of time that would be required to conduct a
discovery scan. Furthermore, the discovery scans conducted by the
wireless transceivers 115 may also be more accurate, as the
wireless transceivers typically operate a higher transmit and
receive power than the mobile device 120 and thus be more sensitive
than the mobile device 120 providing more accurate results.
Furthermore, wireless transceivers 115 that have switched to a
different channel or those do not broadcast an SSID or other
identifier may also be detected more quickly as the discovery scan
can be conducted across multiple channels at once by the wireless
transceivers 115.
[0082] Discovery scan results from the wireless transceivers from
first wireless transceiver list can be received (stage 830), and
discovery scan results from the wireless transceivers from second
wireless transceiver list can be received (stage 835). The scan
results from each of the wireless transceivers 115 can include
information that identifies the wireless transceivers 115 proximate
to that wireless transceiver 115 that were detected during the
scan. In some implementations, the scan results comprise one or
more WLAN Radio Measurement Report frames. The scan results can
include an identifier that identifies which wireless transceiver
115 conducted a scan and is providing scan results. The scan
results can include information such as the channel set and/or
channel number for which the scan results apply, measurement start
and end times and/or measurement duration, and information
identifying one or more wireless transceivers 115 from which
signals were received during the scan. The scan results can also
identify whether a passive or active scan was performed by the
wireless transceiver 115 that conducted the scan.
[0083] The discovery scan results from the scan for wireless
transceivers proximate to the mobile device with the discovery scan
results from the at least one wireless transceiver from the first
wireless transceiver list and the discovery scan results from the
at least one wireless transceiver from the second wireless
transceiver list can then be compared (stage 840). The discovery
scan module 364 of the mobile device can be configured to compare
the results of the discovery scan conducted by the mobile device
120 with the discovery scan results obtained from the wireless
transceivers on the first wireless transceiver list and the
discovery scan results obtained from the wireless transceivers on
the second wireless transceiver list. For example, the discovery
scan module 364 can compare identifiers of wireless transceivers
included first discovery scan results with identifiers of wireless
transceivers included in the second and the third discovery scan
results to identify wireless transceivers included in the first
discovery scan results and also in the second or third discovery
scan results.
[0084] An LCI associated with the portion of the indoor environment
in which the mobile device is located can be determined based at
least in part on the comparison (stage 845). The discovery scan
module 364 and/or the position determination module 362 can be
configured to disambiguate the LCI associated with the mobile
device based on the results of the comparison from stage 840. For
example, if the discovery scan module 364 determines that the
results of the discovery scan conducted by the mobile device 120
includes more of the same wireless transceivers 115 that were
included in the second discovery scan results provided by the
wireless transceivers 115 on the first wireless transceiver list
than were included in the third discovery scan results provided by
the wireless transceivers 115 on the second wireless transceiver
list, the discovery scan module 364 can be configured to maintain
the association of the mobile device 120 with the first LCI which
the mobile device 120 is currently associated. However, if the
discovery scan module 364 determines that the results of the
discovery scan conducted by the mobile device 120 includes more of
the same wireless transceivers 115 that were included in the third
discovery scan results than were included in the second discovery
scan results, the discovery scan module 364 can be configured to
associate the mobile device with a new LCI.
[0085] In some situations, the mobile device 120 may be proximate
to multiple different LCIs. For example, the mobile device 120 may
be located near an atrium, stairway, escalator, or other portion of
an indoor environment where the mobile device 120 can receive
signals from wireless transceivers 115 on multiple floors or
sections of the indoor environment. In such a situation, the second
wireless transceiver list may include wireless transceivers 115
associated with more than one LCI other than the LCI with which the
mobile device is currently associated. In such a situation, the
discovery scan results received from the wireless transceivers 115
of the second wireless transceiver list may be grouped by LCI, such
that discovery scan results from wireless transceivers from the
same LCI are grouped together. When the mobile device 120 makes a
determination whether the mobile device 120 should remain with the
current LCI or transition to a new LCI, the discovery scan module
364 can be configured to select an LCI from the multiple LCIs that
provides a better match than the current LCI based on the number of
wireless transceivers 115 from the scan results associated with
that LCI that match the discovery scan results conducted by the
mobile device 120. For example, the discovery scan module 364 can
be configured to select a new LCI from the plurality of LCIs if the
discovery scan module 364 determines that the results of the
discovery scan conducted by the mobile device 120 includes more of
the same wireless transceivers 115 that were included in the
discovery scan results provided by the wireless transceivers 115 in
the group of wireless transceivers associated with that LCI than
were included in the scan results provided by the wireless
transceivers 115 on the first wireless transceiver list. The
discovery scan module 364 can be configured to select the new LCI
has the most matches when compared to the other LCIs for which
discovery scan results were obtained.
[0086] By disambiguating the LCI, the discovery scan module 364 can
associate the mobile device with an LCI that is most appropriate to
the current location of the mobile device 120. Selecting the
correct LCI to associate with the mobile device can result in the
mobile device 120 being provided location-based services that are
appropriate to the current location of the mobile device. For
example, indoor navigation for a floor associated with the LCI can
be provided to the mobile device 120 and the position determination
module 362 can use this information to provide a user of the mobile
device 120 with navigation instructions for navigating that floor
of the indoor environment. If the wrong LCI were selected,
navigation information associated with a different floor or area of
the indoor environment may be accessed instead of the information
associated with the floor or area in which the mobile device is
actually located.
[0087] The methodologies described herein may be implemented by
various means depending upon the application. For example, these
methodologies may be implemented in hardware, firmware, software,
or any combination thereof. For a hardware implementation, the
processing units may be implemented within one or more application
specific integrated circuits (ASICs), digital signal processors
(DSPs), digital signal processing devices (DSPDs), programmable
logic devices (PLDs), field programmable gate arrays (FPGAs),
processors, controllers, micro-controllers, microprocessors,
electronic devices, other electronic units designed to perform the
functions described herein, or a combination thereof.
[0088] For a firmware and/or software implementation, the
methodologies may be implemented with modules (e.g., procedures,
functions, and so on) that perform the functions described herein.
Any machine-readable medium tangibly embodying instructions may be
used in implementing the methodologies described herein. For
example, software codes may be stored in a memory and executed by a
processor unit. Memory may be implemented within the processor unit
or external to the processor unit. As used herein the term "memory"
refers to any type of long term, short term, volatile, nonvolatile,
or other memory and is not to be limited to any particular type of
memory or number of memories, or type of media. Tangible media
include one or more physical articles of machine readable media,
such as random access memory, magnetic storage, optical storage
media, and so on.
[0089] If implemented in firmware and/or software, the functions
may be stored as one or more instructions or code on a
computer-readable medium. Examples include computer-readable media
encoded with a data structure and computer-readable media encoded
with a computer program. Computer-readable media includes physical
computer storage media. A storage medium may be any available
medium that can be accessed by a computer. By way of example, and
not limitation, such computer-readable media can comprise RAM, ROM,
EEPROM, CD-ROM or other optical disk storage, magnetic disk storage
or other magnetic storage devices, or any other medium that can be
used to store desired program code in the form of instructions or
data structures and that can be accessed by a computer; disk and
disc, as used herein, includes compact disc (CD), laser disc,
optical disc, digital versatile disc (DVD), floppy disk and Blu-ray
disc where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above
should also be included within the scope of computer-readable
media. Such media also provide examples of non-transitory media,
which can be machine readable, and wherein computers are an example
of a machine that can read from such non-transitory media.
[0090] The generic principles discussed herein may be applied to
other implementations without departing from the spirit or scope of
the disclosure or claims.
* * * * *